In order to solve Equation (REF ), we need to compute the expectation \(\tilde{\eta }\)  and the Fisher metric \(g\) . It turns out that these quantities can be computed from the log-partition function. Specifically, [1]}, [2]}, [3]} show that
\(\eta _i = \partial _i\psi \quad \text{and} \quad g_{ij}(\theta ) = \partial _i \partial _j \psi  \) 
